Abstract: A matric potential sensor (100) arranged to measure the matric potential of a medium and comprising a porous material portion (102a, 102b), arranged to absorb moisture from the medium into which, in use, it is inserted, and an electrode element (100) wherein a non-porous compliant material (606, 608) is provided between the porous material (102a, 102b) portion and the electrode element (100).

Abstract: A moisture content sensor for measuring the moisture content of a medium. The sensor includes a probe that injects an electrical signal into the medium. Complex impedance circuitry located between the probe and the electrical signal source allows sensing electronics to generate a signal that represents the moisture content within the medium based on changes in the permittivity of the medium. The complex impedance circuitry minimizes the influence of temperature and conductivity of the medium on the sensed signal. The sensing electronics may be adjusted to optimize the sensor for varying medium conditions and to vary the linearity of the response curve based on volumetric water content of the medium.

Abstract: A moisture content sensor comprising a signal source (400) arranged to provide a signal, a probe (9) arranged to inject the signal into a medium (6) in which the moisture content is to be measured, a complex impedance (4) placed between the probe (9) and the signal source (400) and sensing electronics (7) arranged to monitor the signal at a point between the signal source (400) and the complex impedance (4) and generate a primary measurement therefrom which is indicative of the moisture content of the medium (6).